Stratigraphic column of the Xiazhen Formation with the 18 stromatoporoid-bearing intervals

A diverse labechiid stromatoporoid assemblage that includes 16 species in 8 genera was found in the Upper Ordovician Xiazhen Formation (mid-late Katian) at Zhuzhai, Jiangxi Province of South China. The assemblage is characterized by a combination of: a) North China provincial species succeeding from their origination in the Darriwilian, including Pseudostylodictyon poshanense Ozaki, 1938, Labechia shanhsiensis Yabe and Sugiyama, 1930, Lb. variabilis Yabe and Sugiyama, 1930 and Labechiella regularis (Yabe and Sugiyama, 1930), and b) South China endemic species, including three new species (Lb. zhuzhainus Jeon sp. nov., Lblla. beluatus Jeon sp. nov., Sinabeatricea luteolus Jeon gen. et sp. nov.), and four species in open nomenclature (Rosenella sp., Cystostroma sp., Pseudostylodictyon sp. and Labechia sp.). The finding of Lblla. gondwanense Jeon sp. nov., Stylostroma bubsense Webby, 1991, Sty. ugbrookense Webby, 1991 and Thamnobeatricea gouldi Webby, 1991 in the formation indicates that T...